The present invention relates to an airframe, and more particularly to a thermoplastic matrix airframe section with an in-situ co-bonded thermoplastic fiber cap grid structure and skin which is integrated with a substructure on the fly without subsequent autoclave post processing.
Composite airframe structures for rotary wing aircraft are traditionally fabricated by two techniques: discrete part build up and fully integrated structures. Each of these processes contains various tradeoffs.
The process of manufacturing unique components and subsequently fastening or bonding the plurality of components together is laden with high recurring part cost and non-recurring tooling costs. Each unique composite component requires discrete mold, trim, fixture, and ply location tools or templates. These tools are required for each unique component within the assembly.
Once the plurality of unique individual components are manufactured, they are assembled in an assembly fixture for mechanically fastened structures, or in a bond fixture for bonded structures. Each of these assembly processes requires significant labor associated with lay-up, machine time, and hand assembly.
Fully integrated composite assemblies join the plurality of discrete uncured and cured composite components prior to the cure cycle. This results in a single unitized structure after cure. Although the total quantity of tools for this process may be less than that required for a discrete part assembly, tooling tolerances and quality issues may be more significant. Additionally, although the touch labor associated with a unitized structure is essentially the same prior to cure, a fully integrated composite assembly generally results in reduced touch labor after autoclave curing since less assembly is required. However, relatively expensive non-recurring tooling requires significant time duration for lay-up and cure which significantly limits the amount of product throughput.
In general, fabrication of discrete part build-up with separate, dedicated tooling is costly and time consuming. Fabrication of unitized structures reduces assembly labor, however, tool complexity is increased which reduces product throughput.
Accordingly, it is desirable to provide a composite airframe structural section as an essentially engineered commodity assembly and a method of manufacture therefor which capitalizes on manufacturing economies of scale to achieve lower cost airframe sections.